Thermostatically controlled electric circuit closer



R. A. GRADEN Mgrch 14, 1950 THERMOSTATICA LLY CONTROLLED ELECTRIC CIRCUIT CLOSER Filed Sept. 25, 1947 2 Sheets-Sheet l BWEWUG INVENTOR.

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A TTOR/VEY Bl TALLlC Y Patented Mar. 14, 1950 UNITED STATES PATENT OFFICE THERMOSTATICALLY CONTROLLED ELECTRIC CIRCUIT CLOSER Russell Andrew Graden, Millville, Pa., assignor of two-thirds to Ralph Charles Graden, Harrisburg, Pa.

Application September25, 1947, Serial No. 776,135

8 Claims.

ing and highly sensitive to changes in tempera ture conditions.

Another object of my invention is to provide a construction of an adjustable thermostatic electrical switch which is responsive to temperature changes over a relatively wide range of temperatures.

Another object of my invention is to provide an arrangement of a spring actuated snap switch which is controllable by variations in position of a bi-metallic element operated in accordance with changes in temperature conditions.

Still another object of my invention is to provide an arrangement of an adjustable tempera ture-sensitive element for controlling the operation of a knife switch at predetermined temperatures.

Other and further objects of my invention reside in the simplified construction of the temperature controlled electrical circuit controller set forth more fully in the specification hereinafter following by reference to the appended drawings, in which- Figure l is a front elevational view of the adjustable temperature controlled circuit closer of my invention with the circuit closer shown in circuit open position;

Figure 2 is a side elevational view of the circuit controller illustrated in Figure 1;

Figure 3 is a top plan view of the circuit controller shown in Figures 1 and 2;

Figure 4 is a vertical sectional view taken substantially on the line 44 of Figure 1;

Figure 5 is a vertical sectional view taken substantially on the line 5-5 of Figure 7;

Figure 6 is a transverse sectional view taken substantially on the line GB of Figure 1; and

Figure 7 is a front elevational view of the circuit controller of my invention illustrated in circuit closing position.

My invention is directed to a circuit closer operating under control of a thermostat and arranged for selective actuation over an adjustable range of temperatures. The structure of the device of my invention is very simple, inexpensive in manufacture and production and yet performs a circuit closing operation with a high degree of accuracy. I provide a pivotally mounted adjust- ZOO-139) able arm pivotally supported with respect to an insulated structure and adjustable over a calibrated scale graduated according to temperature. The adjustable arm is connected to a lever memher which may be selectively set in a predetermined position. The lever member insulatingly carries a bi*netallic expansible and contractible member. A knife switch, operative under control of a spring actuator, is arranged to coact with the lei-metallic member and operates in association with contact means to close an electrical circuit under control of the displacement of the bi-metallic member. The angular adjustment of the bi-metallic member determines the position at which displacement of the bi-metallic member permits actuation of the knife switch for ccrrespotiiding control of the associated electrical circui The simplicity of the design of the construction of my invention renders the device reliable for quick response to changes in temperature above or below a selected point with minimum danger of failure due to corrosion, dirt or exposure to the elements. By reason of the ruggedness of the mechanism of the device of my invention I have found the construction particularly adapted for use in the control of warning devices in firm alarm systems. Only a small rise in temperature is required to operate the knife switch device in the mechanism embodied in the structure of my invention so that heat from flames in the general area of the device of my invention is sufficient to trigger off the thermostatic device, operate the knife switch and control a circuit to a Warning system or independ-- ently operated sprinkler system. I have designed the device for installations in the home, factories, and places of business where the device must function over a period of years with mintmum maintenance while subject to conditions of dust, dirt and fumes.

Referring to the drawings in detail, reference character I designates a supporting base structure of insulation material at the top of which there is mounted a scale member 2 carrying graduations 3 thereon calibrated in accordance with the temperature range over which the device operates. An adjustable arm 4 is pivotally mounted on member 5 which passes through the base i. A spacing washer 6 is interposed between the under surface of the adjustable arm 4 and the surface of base i to permit the adjustable arm 4 to be angularly adjustable over the scale member 2. The upper end of the adjustable arm 4 is provided with an indicator pointer 4a having a Sighting edge extending longitudinally along the center line of the adjustable arm 4 and adapted to be selectively aligned with the gradua'tions 3 on scale member 2. The opposite end of the adjustable arm 4 is bifurcated, as indicated at 41), for embracing the headed stud I carried by lever member 8. The headed stud i is spaced from lever member 8 sufficiently to allow the bifurcated end 411 of adjustable arm 4 to be readily adjusted beneath the headed end of stud I so that, as the adjustable arm 4 is angular-1y shifted over scale member 2, an angular adjustment in position of lever member 8 about the pivot 9 is effected. The member 8 is pivoted at 9 on support I, enabling plate 8 to be located about 9 as a center as the adjustable arm is angularly adjusted. The lever 8 carries a block of insulation material It thereon with the sides of the block disposed in off-center with respect to pivot 9. The block It) serves as a mounting means for the bimetallic strip II which is secured by fastening means I2 to block I0. The plane of bi-metallic strip II is displaced from the center 9, about which lever member 8 pivots, for such a distance that the upper end of the bi-metallic strip II moves through a relatively wide angular distance for relatively small angular displacement of the lever member 8. The upper end of the bi-"netallic strip II is bifurcated, as represented at Ila, and serves as a journalling means for a shaft member I4 carrying roller member IS. The roller member I5 is displaceable in a transverse path, with respect to the support I, under control of the movement of adjustable arm 4 and roller member I5 is also displaceable transversely of support I under conditions of expansion or contraction of the components of the bi-metallic strip II.

The electric circuit control, which coact-s with the bi-metallic strip I l, is mounted upon a panel of insulation material designated at I6 secured by fastening means I! to support I. The panel I6 has a conductive plate I8 supported at the upper end thereof, which plate serves as a bearing surface for the knife switch blade I9 which is eccentrically pivoted by means of screw member 20 which passes through plate I8 and into the panel It. The knife blade I9 has one end thereof turned inwardly toward the edge of panel I5, as represented at I9a, the said edge being tapered from a relatively narrow width outwardly to a substantially wider width at the other end and displaceable within the recess IBa formed in the side of panel IS. The widest edge of the tapered portion 19a is apertured at I 92) to receive one end of the coil spring 2|, the other end of which is fixed at 22 to the support I.

The knife blade I9 eccentrically pivoted at 20 projects transversely of the support I and in spaced relation thereto offset from the coil spring 2! and the adjustable arm 4. The terminus of the knife blade I9 is cut away to provide a straight edge 23 extending in a substantially radial line through the pivot 20. The cut away portion 23 thus provides a step-like cut-out or recess 24 in the end of the knife blade I9. The roller member I5, associated with the bi-metallic strip II, is displaceable along the straight edge 23 in the cutout or recess 24. The portion of the switch blade I9, indicated at 25, immediately adjacent the recess 25, serves as a contacting means for establishing electrical connection with the switch jaws 26 mounted on insulated panel I6 when the switch blade 89 is released from the obstruction offered by roller I5. The switch jaws 26 are constituted by a pair of spaced plate members 25: and 26b normally insulated from each other by means of insulation material 21 and secured by means of screws 23 passing through spaced plate members 26a and 2%, but insulatingly spaced to prevent a short circuit between the plate members 26a and 26b. This is accomplished by enlarging the cut-out apertures in plate 252) and extending the separator of insulation material 21 to form a bushing around fastening screws 28 for preventing electrical contact between fastening screws 28 and plate member 281). The plate member 26a has the end 26a canted forwardly at the upper corner thereof to guide the entry of the switch blade I9 into position between plate members 26a and 26b for bridging the electrical circuit therebetween. Plate members 26a and 26b have connecting lugs 26a and 26b" extending therefrom and serving as terminal connections for the leads 29 and 30 respectively. Leads 29 and 30 pass through apertures 29a and 30a in support I and extend to the circuit which is to be controlled.

By arranging the bi-metallic strip Il so that increases in temperature will displace the strip to the left, looking at the elevational views of Figures 1 and 7, increases in temperature will result in displacement of roller I5 out of the restraining position as illustrated in Figure 7, whereupon knife blade I 9, which is normally restrained in the position illustrated in Figure l for maintaining the circuit controller in Open circuit condition, is eccentrically moved about center 26, as illustrated in Figure 7, electrically shunting plate members 26a and 26b and closing the circuit through the conductors 29 and 30. A Warning device, such as an annunciator or buzzer, may be operated, a bell may be sounded, a horn actuated or, in the case of the application of the device of my invention to fire alarms, a sprinkler system may be set into operation. Similarly, if the device is to operate upon a decrease in temperature, the metallic components making up the bimetallic element l I may be so arranged that upon decrease in temperature roller member I 5 will be moved to the left, thereby releasing the eccentrically mounted knife blade I5 and permitting the blade to make contact with plate members 26a and 28b. Adjustment of arm 4 and corresponding displacement of lever 8 so positions roller member I5, with respect to straight edge 23 of knife blade I9, that the time of operation of the circuit controller may be accurately preset in accordance with temperature conditions. The straight edge 23 serves as a cam member in association with roller I5 where roller I5 normally rides along arm 23 continuously supporting the eccentrically mounted plate I9. Accordingly, in order that a proper setting may be had of roller I5 for a corresponding setting of adjustable arm 4 over the calibrations on the graduated scale 2, the range of the cam 23 is directly proportional to the temperature range over which the device is adjustable. However, when that temperature condition is reached at which bi-metallic member II shifts roller member I5 to a position no longer supporting blade I9, the circuit closing operation is effected. After each circuit closing operation the device must be reset for subsequent repeat operations.

I have found the construction of my invention very reliable and practical and, while I have disclosed my invention in one of its preferred embodiments, I realize that modifications in structure and arrangement may be made, and I de.

panel for engagement and disengagement with.

said contact members and extending in spaced relation to said base support and terminating in a cam-faced edge portion, spring means normally urging said switch blade into connection with said contact members, a thermo-sensitive element supported at one end with respect to said base and engageable at the other end with the camfaced edge portion of said switch blade for normally maintaining said switch blade out of en- 1 gagement with said contact members, a calibrated scale carried by said base support means for adjusting the relative position of said thermo-sensitive element and the cam-faced edge portion of said switch blade for predetermining the time of connection of said switch blade with respect to said contact members according to a selected temperature, and an indicator movable by said means with respect to said calibrated scale.

2. A thermostatically controlled switch comprising a base support of insulation material, a panel of insulation material mounted thereon, a pair of electrical contact members insulatingly supported with respect to each other on said panel, a switch blade pivotally mounted on said panel for engagement and disengagement with said contact members and extending in spaced relation to said base support and terminating in a cam-faced edge portion, spring means normally urging said switch blade into connection with said contact members, a lever member pivotally mounted on said base support, a thermo-sensitive strip member carried by said lever member and terminating in a supporting end normally engaging the cam-faced edge of said switch blade and obstructing the movement of said switch blade into connection with said contact members, a calibrated scale carried by said base support means for adjusting the position of said lever member for predetermining the time of connection of said switch blade with respect to said contact members according to a selected temperature, and an indicator movable by said means with respect to said calibrated scale.

3. A thermostatically controlled switch comprising a base support of insulation material, a panel of insulation material mounted thereon, a pair of electrical contact members insulatingly supported with respect to each other on said panel, a switch blade pivotally mounted on said panel for engagement and disengagement with said contact members and extending in spaced relation to said base support and terminating in a cam-faced edge portion, spring means normally urging said switch blade into connection with said contact members, a lever member pivotally mounted at one end on said base support and carrying a stud member on the opposite end, an adjusting arm pivoted on said base support and bifurcated at one end for engaging said stud member and provided with an indicator on the opposite end, a calibrated scale mounted on said base support in a position beneath said indicator, an insulation member carried by said lever memher, a thermoesensitive element mounted on said insulation member and terminating in a position engaging the cam-faced. edge portion of said switch blade for normally obstructing the engagement of said Switchblade with said contact meme, bers whereby said adjusting arm operates over said calibrated scale for predetermining the time of connection of said switch blade with said contact members according to a selected temperature.

4. A thermostatically controlled switch com-' prising a base support of insulation material, a panel of insulation material mounted thereon, a pair of electrical contact members insulatingly supported with respect to each other on said panel, a switch blade pivotally mounted on said said contact members and extending in spaced relation to said base support and terminating in a cam-faced edge portion, spring means normally urging said switch blade into connection with said contact members, a lever member pivotally mounted at one end on said base support and carrying a stud member on the opposite end, an adjusting arm pivoted On said base support and bifurcated at one end for engaging said stud member and provided with an indicator on the opposite end, a calibrated scalemounted on said base support in a position beneath said indicator, an insulation member carried by said lever member, a thermo-sensitive element constituted by a bi-metallic strip supportedlby said lever member and extending in a plane substantially normal to the plane of said lever member and offset from a center line extending through the pivotal mounting of said lever member and means carried by the end of said bi-metallic strip and normally engaging the cam-faced edge of said switch blade obstructing the movement of said switch blade into engagement with said contact members whereby said adjusting arm operatesover said calibrated scale for predetermining the time of connection of said switch blade with said contact members according to a selected temperature.

5. A thermostatically controlled switch comprising a base support of insulation material, a panel of insulation material mounted thereon, a

pair of electrical contact members insulatinglyv supported with respect to each other on said panel, a switch blade eccentrically mounted on said panel and swingable in an orbit for establishing connection with said contact members, an angularly disposed extension on the eccentrically mounted end of said switch blade directed over one edge of said panel, a tension coil spring connected at one end to said base support and at the other end to the angularly disposed extension of said switch blade for normally urging said switch blade in a direction establishin connection with said contact members, said switch blade terminating in a cam-faced edge portion, a thermo-sensitive element supported at one end with respect to said base and engageable at the other end with said cam-faced edge portion of said switch blade for normally obstructing the movement of said switch blade into connection with said contact members, and means for angularly adjusting the position of said thermosensitive element for effectin a release of the cam-faced edge portion of said switch blade at a predetermined temperature.

6. A thermostatically controlled switch comprising a base support of insulation material, a panel of insulation material mounted thereon, a

to l

pair of electrical contact members insulatingly supported with respect to each other on said panel, a switch blade pivotally mounted on said panel for engagement and disengagement with said contact members and extending in spaced relation to said base support and terminatin in a cam-faced edge portion, spring means normally urging said switch blade into connection with said contact member, a thermo-sensitive element supported at one end with respect to said base and carrying a roller member at the other end engageable with the cam-faced edge portion of said switch blade, for normally obstructing the movement of said switch blade toward said contact members, a calibrated scale carried by said base support means for adjusting the relative position of said thermo-sensitive element and the cam-faced edge portion of said switch blade, and an indicator movable by said means with respect to said calibrated scale.

'7. A thermostatically controlled switch comprising a base support of insulation material, a panel of insulation material mounted thereon, a pair of electrical contact members insulatingly supported with respect to each other on said panel, a switch blade pivotally mounted on said panel for engagement and disengagement with said contact members and extending in spaced relation to said base support and terminating in a cam-faced edge portion, spring means normally urging said switch blade into connection with said contact members, a lever member pivoted on said base support, a calibrated scale carried by said base support adjacent said lever member, a thermo-sensitive element supported at one end with respect to said lever member and terminating in a bifurcated portion at the other end thereof, a roller member journaled in said bifurcated portion and engageable with the camfaced edge portion of said switch blade for normally maintaining said switch blade out of engagement with said contact members, means for moving said lever member for adjusting the relative position of said thermo-sensitive element with respect to said base and with respect to said switch blade for predetermining the position of said roller member along the cam-faced edge portion of said switch blade and an indicator connected with said lever member and movable over said'calibrated scale whereby displacement of said thermo-sensitive element under conditions of changes in temperature operates to release the support offered to the cam-faced edge portion of said switch blade by said roller member for effecting the closing of an electrical circuit between said switch blade and said contact members.

8. A thermostatically controlled switch comprising a base support of insulation material, a panel of insulation material mounted thereon, a pair of electrical contact members insulatingly supported with respect to each other on said panel, one of said electrical contact members having one corner thereof canted outwardly, a switch blade pivotally mounted on said panel and swingable in an orbit to a position guided by the outwardly canted contact member to a position shunting said contact members, spring means for normally urging said switch blade into said shunting position, a calibrated scale carried by said base support, a lever member pivotally mounted at one end on said base support, a thermo-sensitive element supported at one end with respect to said lever member and engageable at its other end with said switch blade for mantaining said switch blade out of contact relation with said contact members until displaced by changes in temperature to a position releasing said switch blade for operation under control of said spring means for shunting said contact members, means for adjusting the position of said lever member, and an indicator connected with said lever member and movable over said calibrated scale.

RUSSELL ANDREW GRADEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,069,531 Copeman Aug. 5, 1913 1,997,604 Stewart Apr. 16, 1935 FOREIGN PATENTS Number Country Date 716,147 France c. Oct. 5, 1931 

